Surgical apparatus for retracting animal tissue during invasive surgical procedures are well known in the art. In their most simple form, surgical retractors can comprise a hand-held device, typically made of surgical-grade stainless steel or other rigid material, having tissue-engaging projections which the surgeon or surgical assistant utilizes to engage and displace tissue manually from the surgical field of operation. More complex retracting devices include parallel tissue engaging appendages projecting from scissor-like or screw-jack structures which can be adjusted by the surgeon to separate the tissue-engaging paddles from one another after they have been inserted into a surgical incision. As those skilled in the art appreciate, the projecting scissor- or screw-adjusting structures must be sufficiently large to allow the tissue-contacting projections or jaws to open sufficiently in order to facilitate surgical access to the field of operation. Whether manipulated by hand or adjusted in place, these prior art surgical retracting apparatus all include bulky structures projecting out from the surgical field within the patient's body. One of the most dramatic examples of such a medical device is the surgical retractor used for "cracking the chest" during open heart surgery where the patient's rib cage is separated at the sternum and held open by the retractor while the surgeon or surgical team accesses the patient's heart.
Recently, advancing trends in medical practice have lead to the development of "minimally invasive" surgical procedures designed to reduce or substantially eliminate the majority of physical trauma experienced by the patient. An exemplary minimally invasive procedure is the limited or "minithoracotomy" wherein one or more small incisions are made in the rib cage rather than splitting the patient's chest open. In such a minimally invasive approach, smaller external retractors are positioned within the incisions and mechanically opened to separate the chest wall tissue and provide access to the interior chest cavity and the heart. The surgeon is then able to make incisions in the heart tissue in order to provide access to internal heart structures.
Surgery upon the heart itself is illustrative of the drawbacks associated with conventional, prior art surgical retractors. Because of their relatively bulky projecting operating structures, conventional retractors are not well suited for use within the crowded confines of small, minimally invasive surgical incisions. Even hand-held retractors require the projecting manipulating handles to extend through the incision which further reduces the space available for surgical operation while obstructing visual access to the surgical field. As a result, conventional approaches to retraction of heart tissue itself typically involve temporarily sewing the heart tissue encroaching on the incision to adjacent tissue within the chest cavity and drawing the sutures tight to hold the encroaching tissue out of the way. Upon completion of the surgical procedure, the securing sutures are removed to allow the tissue to return to its normal position where the incision can be closed permanently. Compounding matters, surgical procedures executed deep within the heart, such as a mitral valve replacement, are difficult to visualize due to inadequate lighting. Unlike conventional open heart surgery where the heart is exposed to ambient lighting and external spot sources of light, minimally invasive procedures provide access to the interior of the heart through relatively narrow channels which are difficult to illuminate, particularly with conventional retractors in place.
Accordingly, in view of the foregoing, it is an object of the present invention to provide surgical apparatus and associated methods of use for retracting tissue which eliminate many of the drawbacks associated with prior art surgical retractors.
It is an additional object of the present invention to provide such surgical apparatus and methods for retracting tissue which atraumatically provide the surgeon with unobstructed access and enhanced viewing of the surgical field.
It is yet another object of the present invention to provide surgical apparatus for retracting tissue which do not require bulky external handles or projecting operating mechanisms.